Remove SmallVec in favor of using a long-term Vec

[jonhoo]

See #78 (comment). Specifically, currently we use a SmallVec for temporarily holding inlined java method calls:

inferno/src/collapse/perf.rs

Lines 278 to 279 in 10a1fd7

	let mut java_inline =
	SmallVec::<[String; 1]>::with_capacity(rawfunc.split("->").count() + 1);

However, in #78, @Licenser decided to instead re-use a Vec in the Folder, which seems like a better strategy since it generally won't allocate even if there are inlined method calls (unlike SmallVec, which will allocate every time that happens).