Update to Checker Framework 3.48.0 (#1030)

Fixes #1012.
[Benchmarking](#1030 (comment))
shows any perf difference is within the noise.

gradle/dependencies.gradle

@@ -40,7 +40,7 @@ if (project.hasProperty("epApiVersion")) {
 
 def versions = [
     asm                    : "9.3",
-    checkerFramework       : "3.43.0",
+    checkerFramework       : "3.48.0",
     // for comparisons in other parts of the build
     errorProneLatest       : latestErrorProneVersion,
     // The version of Error Prone used to check NullAway's code.

nullaway/src/test/java/com/uber/nullaway/CoreTests.java

@@ -1053,4 +1053,20 @@ public void testStaticImportFromSubclass() {
             "}")
         .doTest();
   }
+
+  /** testing for no Checker Framework crash */
+  @Test
+  public void ternaryBothCasesNull() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "TestCase.java",
+            "package com.uber;",
+            "import org.jspecify.annotations.Nullable;",
+            "public class TestCase {",
+            "    public static @Nullable String foo(String x) {",
+            "        return x.isEmpty() ? null : null;",
+            "    }",
+            "}")
+        .doTest();
+  }
 }