Fix thisPredicateFunction{Completions,QuickInfo}02 tests.

The Crate<T> class had a "this" type predicate that referenced the type
parameter T, preventing T from being covariant, which caused unexpected
behavior elsewhere.  Apply the workaround of giving the method its own
type parameter T to avoid affecting the variance of the class's T.

Author: mattmccutchen

tests/cases/fourslash/thisPredicateFunctionCompletions02.ts

@@ -12,7 +12,7 @@
 ////     contents: T;
 ////     isSundries(): this is Crate<Sundries>;
 ////     isSupplies(): this is Crate<Supplies>;
-////     isPackedTight(): this is (this & {extraContents: T});
+////     isPackedTight<T>(this: Crate<T>): this is {extraContents: T};
 //// }
 //// const crate: Crate<any>;
 //// if (crate.isPackedTight()) {

tests/cases/fourslash/thisPredicateFunctionQuickInfo02.ts

@@ -12,7 +12,7 @@
 ////     contents: T;
 ////     /*1*/isSundries(): this is Crate<Sundries>;
 ////     /*2*/isSupplies(): this is Crate<Supplies>;
-////     /*3*/isPackedTight(): this is (this & {extraContents: T});
+////     /*3*/isPackedTight<T>(this: Crate<T>): this is {extraContents: T};
 //// }
 //// const crate: Crate<any>;
 //// if (crate.isPackedTight/*4*/()) {
@@ -34,18 +34,18 @@
 verify.quickInfos({
     1: "(method) Crate<T>.isSundries(): this is Crate<Sundries>",
     2: "(method) Crate<T>.isSupplies(): this is Crate<Supplies>",
-    3: `(method) Crate<T>.isPackedTight(): this is this & {
+    3: `(method) Crate<T>.isPackedTight<T>(this: Crate<T>): this is {
     extraContents: T;
 }`,
-    4: `(method) Crate<any>.isPackedTight(): this is Crate<any> & {
+    4: `(method) Crate<any>.isPackedTight<any>(this: Crate<any>): this is {
     extraContents: any;
 }`,
     5: "(method) Crate<any>.isSundries(): this is Crate<Sundries>",
-    6: `(method) Crate<Sundries>.isPackedTight(): this is Crate<Sundries> & {
+    6: `(method) Crate<Sundries>.isPackedTight<Sundries>(this: Crate<Sundries>): this is {
     extraContents: Sundries;
 }`,
     7: "(method) Crate<any>.isSupplies(): this is Crate<Supplies>",
-    8: `(method) Crate<Supplies>.isPackedTight(): this is Crate<Supplies> & {
+    8: `(method) Crate<Supplies>.isPackedTight<Supplies>(this: Crate<Supplies>): this is {
     extraContents: Supplies;
 }`
 });