Add integration test for --remap-pathh-prefix

Author: jyn514

src/test/incremental/commandline-args.rs

@@ -2,20 +2,23 @@
 // the cache while changing an untracked one doesn't.
 
 // ignore-asmjs wasm2js does not support source maps yet
-// revisions:rpass1 rpass2 rpass3
+// revisions:rpass1 rpass2 rpass3 rpass4
 // compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 
 #![rustc_partition_codegened(module="commandline_args", cfg="rpass2")]
 #![rustc_partition_reused(module="commandline_args", cfg="rpass3")]
+#![rustc_partition_codegened(module="commandline_args", cfg="rpass4")]
 
 // Between revisions 1 and 2, we are changing the debuginfo-level, which should
 // invalidate the cache. Between revisions 2 and 3, we are adding `--verbose`
-// which should have no effect on the cache:
+// which should have no effect on the cache. Between revisions, we are adding
+// `--remap-path-prefix` which should invalidate the cache:
 //[rpass1] compile-flags: -C debuginfo=0
 //[rpass2] compile-flags: -C debuginfo=2
 //[rpass3] compile-flags: -C debuginfo=2 --verbose
+//[rpass4] compile-flags: -C debuginfo=2 --verbose --remap-path-prefix=/home/bors/rust=src
 
 pub fn main() {
     // empty

src/test/run-make-fulldeps/incr-add-rust-src-component/Makefile

@@ -1,7 +1,7 @@
 -include ../tools.mk
 
 # rust-lang/rust#70924: Test that if we add rust-src component in between two
-# incremetnal compiles, the compiler does not ICE on the second.
+# incremental compiles, the compiler does not ICE on the second.
 
 # This test uses `ln -s` rather than copying to save testing time, but its
 # usage doesn't work on windows. So ignore windows.