[AMDGPU] Fix test difference in debug and release. NFC.

Added -disable-gisel-legality-check to couple GlobalISel tests
which have not legal instructions to avoid difference in
debug and release builds.

llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-load-local.mir

 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
-# RUN: llc -march=amdgcn -mcpu=tahiti -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX6 %s
+# RUN: llc -march=amdgcn -mcpu=tahiti -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -disable-gisel-legality-check -o - %s | FileCheck -check-prefix=GFX6 %s
 # RUN: llc -march=amdgcn -mcpu=hawaii -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX7 %s
 # RUN: llc -march=amdgcn -mcpu=fiji -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX7 %s
 # RUN: llc -march=amdgcn -mcpu=gfx900 -run-pass=instruction-select -verify-machineinstrs -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX9 %s
@@ -406,7 +406,8 @@ body: |
     ; GFX6: liveins: $vgpr0
     ; GFX6-NEXT: {{  $}}
     ; GFX6-NEXT: [[COPY:%[0-9]+]]:vgpr(p3) = COPY $vgpr0
-    ; GFX6-NEXT: [[LOAD:%[0-9]+]]:vgpr(p1) = G_LOAD [[COPY]](p3) :: (load (p1), align 4, addrspace 3)
+    ; GFX6-NEXT: $m0 = S_MOV_B32 -1
+    ; GFX6-NEXT: [[LOAD:%[0-9]+]]:vreg_64(p1) = G_LOAD [[COPY]](p3) :: (load (p1), align 4, addrspace 3)
     ; GFX6-NEXT: $vgpr0_vgpr1 = COPY [[LOAD]](p1)
     %0:vgpr(p3) = COPY $vgpr0
     %1:vgpr(p1) = G_LOAD %0 :: (load (p1), align 4, addrspace 3)

llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-store-local.mir

 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
-# RUN: llc -march=amdgcn -mcpu=tahiti -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX6 %s
+# RUN: llc -march=amdgcn -mcpu=tahiti -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -disable-gisel-legality-check -o - %s | FileCheck -check-prefix=GFX6 %s
 # RUN: llc -march=amdgcn -mcpu=hawaii -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX7 %s
 # RUN: llc -march=amdgcn -mcpu=fiji -run-pass=instruction-select -verify-machineinstrs  -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX7 %s
 # RUN: llc -march=amdgcn -mcpu=gfx900 -run-pass=instruction-select -verify-machineinstrs -global-isel-abort=0 -o - %s | FileCheck -check-prefix=GFX9 %s
@@ -350,6 +350,7 @@ body: |
     ; GFX6-NEXT: {{  $}}
     ; GFX6-NEXT: [[COPY:%[0-9]+]]:vgpr(p1) = COPY $vgpr0_vgpr1
     ; GFX6-NEXT: [[COPY1:%[0-9]+]]:vgpr(p3) = COPY $vgpr2
+    ; GFX6-NEXT: $m0 = S_MOV_B32 -1
     ; GFX6-NEXT: G_STORE [[COPY]](p1), [[COPY1]](p3) :: (store (p1), align 4, addrspace 3)
     %0:vgpr(p1) = COPY $vgpr0_vgpr1
     %1:vgpr(p3) = COPY $vgpr2
@@ -437,6 +438,7 @@ body: |
     ; GFX6-NEXT: {{  $}}
     ; GFX6-NEXT: [[COPY:%[0-9]+]]:vgpr(<4 x s16>) = COPY $vgpr0_vgpr1
     ; GFX6-NEXT: [[COPY1:%[0-9]+]]:vgpr(p3) = COPY $vgpr2
+    ; GFX6-NEXT: $m0 = S_MOV_B32 -1
     ; GFX6-NEXT: G_STORE [[COPY]](<4 x s16>), [[COPY1]](p3) :: (store (<4 x s16>), align 4, addrspace 3)
     %0:vgpr(<4 x s16>) = COPY $vgpr0_vgpr1
     %1:vgpr(p3) = COPY $vgpr2