Fix query string parsing time regression

Summary: D71483524 Introduced an inadvertent N^2 search for target_literal strings in the query string to save memory. We're guaranteed the `l` literal here is a substring of the main query string, and can use that to compute the offset/len directly with pointer arithmatic, and save the searches.

Reviewed By: JakobDegen

Differential Revision: D72821365

fbshipit-source-id: 62822444dddb1f2eda82bb943569a9fd151d2265

Author: Jeremy Braun

app/buck2_interpreter_for_build/src/attrs/coerce/attr_type/query.rs

@@ -77,8 +77,9 @@ impl QueryAttrTypeExt for QueryAttrType {
                 .into_iter()
                 .map(|(l, p)| {
                     query
-                        .find(l)
-                        .map(|offset| ((offset, l.len()), p))
+                        .as_str()
+                        .substr_range(l)
+                        .map(|range| ((range.start, range.len()), p))
                         .internal_error("Not found in query")
                 })
                 .try_collect()?,

app/buck2_interpreter_for_build/src/lib.rs

@@ -10,6 +10,7 @@
 #![feature(error_generic_member_access)]
 #![feature(try_blocks)]
 #![feature(iterator_try_collect)]
+#![feature(substr_range)]
 
 use std::sync::Once;