AMDGPU: Explicitly disable verifier in failing tests

This should fix expensive_checks failures.

These now hit a new verifier error. The first test is explicitly
testing the failing case produces an error, so it should skip
the verifier. The unsupported call tests should also error (although
it would be better if it errored via a different path).

Author: arsenm

llvm/test/CodeGen/AMDGPU/illegal-sgpr-to-vgpr-copy.ll

@@ -1,5 +1,5 @@
-; RUN: not llc -mtriple=amdgcn < %s 2>&1 | FileCheck -check-prefix=ERR %s
-; RUN: not llc -mtriple=amdgcn < %s 2>&1 | FileCheck -check-prefix=GCN %s
+; RUN: not llc -mtriple=amdgcn -verify-machineinstrs=0 < %s 2>&1 | FileCheck -check-prefix=ERR %s
+; RUN: not llc -mtriple=amdgcn -verify-machineinstrs=0 < %s 2>&1 | FileCheck -check-prefix=GCN %s
 
 ; ERR: error: <unknown>:0:0: in function illegal_vgpr_to_sgpr_copy_i32 void (): illegal VGPR to SGPR copy
 ; GCN: ; illegal copy v1 to s9

llvm/test/CodeGen/AMDGPU/unsupported-calls.ll

@@ -1,5 +1,5 @@
-; RUN: not llc -mtriple=amdgcn-mesa-mesa3d -tailcallopt < %s 2>&1 | FileCheck --check-prefix=GCN %s
-; RUN: not llc -mtriple=amdgcn--amdpal -tailcallopt < %s 2>&1 | FileCheck --check-prefix=GCN %s
+; RUN: not llc -mtriple=amdgcn-mesa-mesa3d -tailcallopt -verify-machineinstrs=0 < %s 2>&1 | FileCheck --check-prefix=GCN %s
+; RUN: not llc -mtriple=amdgcn--amdpal -tailcallopt -verify-machineinstrs=0 < %s 2>&1 | FileCheck --check-prefix=GCN %s
 ; RUN: not llc -mtriple=r600-- -mcpu=cypress -tailcallopt < %s 2>&1 | FileCheck -check-prefix=R600 %s
 
 declare i32 @external_function(i32) nounwind