[WebAssembly] Simplify regcopy.mir

[aheejin]

Summary

This deletes the ll templates from the functions because they don't need
them (mir files need ll templates only when they have function calls or
BB names that are not numbers).

This also renames the filename to reg-copy.mir, because I'm planning
to add some more reg-*.mir soon.

[aheejin]

reg_instr.mir -> reg-instr.mir

[aheejin]

Cancel renaming

[aheejin]

regcopy.mir -> reg-copy.mir

llvm/test/CodeGen/WebAssembly/reg_instr.mir

-# RUN: llc %s -o - -run-pass=postrapseudos | FileCheck %s
---- |
-  target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
-  target triple = "wasm32-unknown-unknown"
+# RUN: llc -mtriple=wasm32-unknown-unknown %s -o - -run-pass=postrapseudos | FileCheck %s
 
-  define void @copy_i32() {
-    ret void
-  }
-
-  define void @copy_i64() {
-    ret void
-  }
-
-  define void @copy_f32() {
-    ret void
-  }
-
-  define void @copy_f64() {
-    ret void
-  }
-
-  define void @copy_v128() {
-    ret void
-  }
-...
 ---
 name: copy_i32
 # CHECK-LABEL: copy_i32
-body:             |
+body: |
   ; CHECK-LABEL: bb.0:
   ; CHECK-NEXT: %0:i32 = COPY_I32 %1:i32
   ; CHECK-NEXT: RETURN_VOID
   bb.0:
     %0:i32 = COPY %1:i32
     RETURN_VOID implicit-def $arguments
 ...
 ---
 name: copy_i64
 # CHECK-LABEL: copy_i64
 body:             |
   ; CHECK-LABEL: bb.0:
   ; CHECK-NEXT: %0:i64 = COPY_I64 %1:i64
   ; CHECK-NEXT: RETURN_VOID
   bb.0:
     %0:i64 = COPY %1:i64
     RETURN_VOID implicit-def $arguments
 ...
 ---
 name: copy_f32
 # CHECK-LABEL: copy_f32
-body:             |
+body: |
   ; CHECK-LABEL: bb.0:
   ; CHECK-NEXT: %0:f32 = COPY_F32 %1:f32
   ; CHECK-NEXT: RETURN_VOID
   bb.0:
     %0:f32 = COPY %1:f32
     RETURN_VOID implicit-def $arguments
 ...
 ---
 name: copy_f64
 # CHECK-LABEL: copy_f64
-body:             |
+body: |
   ; CHECK-LABEL: bb.0:
   ; CHECK-NEXT: %0:f64 = COPY_F64 %1:f64
   ; CHECK-NEXT: RETURN_VOID
   bb.0:
     %0:f64 = COPY %1:f64
     RETURN_VOID implicit-def $arguments
 ...
 ---
 name: copy_v128
 # CHECK-LABEL: copy_v128
-body:             |
+body: |
   ; CHECK-LABEL: bb.0:
   ; CHECK-NEXT: %0:v128 = COPY_V128 %1:v128
   ; CHECK-NEXT: RETURN_VOID
   bb.0:
     %0:v128 = COPY %1:v128
     RETURN_VOID implicit-def $arguments
 ...