Put RubyVM::MJIT::Compiler under ruby_vm directory (#6989)

[Misc #19250]

.gitignore

@@ -238,7 +238,7 @@ lcov*.info
 
 # MJIT
 /include/ruby-*/*/rb_mjit_min_header-*.h
-/lib/mjit/instruction.rb
+/lib/ruby_vm/mjit/instruction.rb
 /mjit_config.h
 /rb_mjit_header.h
 

common.mk

@@ -235,9 +235,9 @@ all: $(SHOWFLAGS) main docs
 main: $(SHOWFLAGS) exts $(ENCSTATIC:static=lib)encs
 	@$(NULLCMD)
 
-main: $(srcdir)/lib/mjit/instruction.rb
-srcs: $(srcdir)/lib/mjit/instruction.rb
-$(srcdir)/lib/mjit/instruction.rb: $(tooldir)/insns2vm.rb $(tooldir)/ruby_vm/views/lib/mjit/instruction.rb.erb $(srcdir)/insns.def
+main: $(srcdir)/lib/ruby_vm/mjit/instruction.rb
+srcs: $(srcdir)/lib/ruby_vm/mjit/instruction.rb
+$(srcdir)/lib/ruby_vm/mjit/instruction.rb: $(tooldir)/insns2vm.rb $(tooldir)/ruby_vm/views/lib/ruby_vm/mjit/instruction.rb.erb $(srcdir)/insns.def
 	$(ECHO) generating $@
 	$(Q) $(BASERUBY) -Ku $(tooldir)/insns2vm.rb --basedir="$(srcdir)" $(INSNS2VMOPT) $@
 

mjit.rb

@@ -20,10 +20,10 @@ if RubyVM::MJIT.enabled?
     return # miniruby doesn't support MJIT
   end
 
-  RubyVM::MJIT::C = Object.new # forward declaration for mjit/compiler
-  require "mjit/c_type"
-  require "mjit/instruction"
-  require "mjit/compiler"
+  RubyVM::MJIT::C = Object.new # forward declaration for ruby_vm/mjit/compiler
+  require 'ruby_vm/mjit/c_type'
+  require 'ruby_vm/mjit/instruction'
+  require 'ruby_vm/mjit/compiler'
 
   module RubyVM::MJIT
     private_constant(*constants)