auto merge of #6237 : dotdash/rust/reduce_bloat, r=brson

In commit d7f5e437 "core::rt: Add the local heap to newsched tasks",
local_malloc and local_free have become rather big and their forced
inlining causes quite a bit of code bloat. Compile times for crates
affected by the bloat (e.g. rustc) improve, while others (e.g. libstd)
seem to be unaffected, so I guess the inlining doesn't gain us much.

Sizes:
```
               | librustc   | libsytax
---------------|–-----------|------------
with inlining  | 18,547,824 |  7,110,848
w/o inlining   | 15,092,040 |  5,518,608

src/libcore/unstable/lang.rs

@@ -98,7 +98,6 @@ pub unsafe fn local_malloc(td: *c_char, size: uintptr_t) -> *c_char {
 }
 
 #[lang="malloc"]
-#[inline(always)]
 #[cfg(not(stage0))]
 pub unsafe fn local_malloc(td: *c_char, size: uintptr_t) -> *c_char {
     match context() {
@@ -129,7 +128,6 @@ pub unsafe fn local_free(ptr: *c_char) {
 // inside a landing pad may corrupt the state of the exception handler. If a
 // problem occurs, call exit instead.
 #[lang="free"]
-#[inline(always)]
 #[cfg(not(stage0))]
 pub unsafe fn local_free(ptr: *c_char) {
     match context() {