[NFC] These tests require a default target

These test cases all rely on a default target being specified. Adding
the requirement gets the tests properly skipped when
LLVM_DEFAULT_TARGET_TRIPLE is unset.

llvm/test/CodeGen/MLRegalloc/default-eviction-advisor.ll

@@ -2,6 +2,7 @@
 ; trying to use ML-driven advisor.
 ; REQUIRES: !have_tf_aot
 ; REQUIRES: !have_tf_api
+; REQUIRES: default_target
 ; RUN: not llc -O2 -regalloc-enable-advisor=development < %s 2>&1 | FileCheck %s
 ; RUN: not llc -O2 -regalloc-enable-advisor=release < %s 2>&1 | FileCheck %s
 ; RUN: llc -O2 -regalloc-enable-advisor=default < %s 2>&1 | FileCheck %s --check-prefix=DEFAULT

llvm/test/DebugInfo/dwarfdump-immutable.ll

@@ -1,6 +1,6 @@
 ;; This test checks whether DWARF tag DW_TAG_immutable_type
 ;; is accepted and processed.
-
+; REQUIRES: default_target
 ; RUN: %llc_dwarf %s -filetype=obj -o - | llvm-dwarfdump - | FileCheck %s
 
 ;; Test whether DW_TAG_immutable_type is accepted.

llvm/test/tools/llc/binutils-version.ll

@@ -1,4 +1,5 @@
 ;; Test valid and invalid -binutils-version values.
+; REQUIRES: default_target
 ; RUN: llc %s -filetype=null -binutils-version=none
 ; RUN: llc %s -filetype=null -binutils-version=2
 ; RUN: llc %s -filetype=null -binutils-version=2.35

llvm/test/tools/llc/filetype-null-stop-after.ll

@@ -1,3 +1,4 @@
 ; -stop-after would normally dump MIR, but with -filetype=null as well check
 ; there's no output at all.
+; REQUIRES: default_target
 ; RUN: llc -filetype=null -stop-after=finalize-isel -o - %s | count 0

llvm/test/tools/llc/time-trace.ll

@@ -1,3 +1,4 @@
+; REQUIRES: default_target
 ; RUN: llc -o /dev/null -O2 -time-trace -time-trace-granularity=100 -time-trace-file=%t.json
 ; RUN: FileCheck --input-file=%t.json %s
 

llvm/test/tools/llvm-lto/ltomodule.ll

@@ -1,5 +1,5 @@
 # RUN: rm -rf %t && split-file %s %t
-
+; REQUIRES: default_target
 ; RUN: llvm-as < %t/hasCtor.ll > %t.bc
 ; RUN: llvm-lto %t.bc -query-hasCtorDtor | FileCheck %s --check-prefixes=POSITIVE